Radio receiving system



Filed April 50, 1950 INVENTORY HE. OVERACKVER ATTORNEY Patented Aug. 23, 1932 NITED i HORACE OVERACKER, or rate ALTO, cnmronniniinssienon ico'f IBEDEBAL GRAPH COMPANY, OF sen rimnoisco onmnonnne;ii conronnmroiv or .cALIFoIa NIA i RADIQIBEGEIYINQ-SYS'I'EM This invention relates to'radio receiving the positive terminal of thefilamentd' by .systemsand particularly to systems for re; ceiving extremely high frequency continu; impedancefor 'th'e radijo"frequencycurrent ous wave telegraph signals. component in theoutputl of' the detector, and

A broad object of the invention is to proradio" frequency 'chokeco'il 23 serves to vide a receiver which is extremely'sensitive keep this component" frornl 'the audio freand selective and yet stable in operation and simple in construction. 7

In brief, the receiver in accordance with the present invention comprises a regeneraf tive amplifier and a detector tube with a chopper (for breaking up the received continuous wave) inserted between the amplifier and the detector tube. i

The single figure of the drawing constia tutes a schematic diagram showing the pre-d ferred circuit of the invention.

Referring to the drawing a detectortubeh 2 has, as an element of its input circuit,:a 20 coil 1, which is connected between the oath-1. ode 3 and grid 4 of the tube. Coil 1 is inductively coupled to a second coil 5, which is,, in turn, coupled to an antenna circuit 6.

To reduce the losses in the receiving cir-. cuit, a regenerative tube 11 is provided. The

of any wellknown'typeand isc oupled'to the output circuit of d-etectortube '2tli rough an audio frequency transformer 24. A chopper, schematically shown at 25,"is' connected in series with a' cond'enser 26 across the input 'm'ay consist of" any -suitable' contact device capable of opening and 'closing its contacts 'at a tone frequency:

In operation,';the circuit i's'tunedto the fre-' quency: of the'desired wave by} adj usting condensers-9 and 20. "Since the settingof condenser 20 also determines the amount of regeneration produced by tube 11, these two controls (condensers Qan'd 20) are manipthe proper tuning andalso theproper amount 1 of regeneration: -With tube 11 adjusted to a input circuit of this tube, comprises cathode highly regenerativec'onditiomthe energy fed back through the'tube'; capacity from the out- 12, coil'fi and grid 13, and the output circuit" 7 "put circuit to the'input circuit issuflicient to comprises anode 14, coil 15, series condenser 20, and cathode 12. The cathodel2 is con-2 nected' to a source of he ting current 16, a d 'receiving circuit. Hence, any slight? potential a source of anode potential 18 is connected applied to antenna 6-bygan incoming-radio to the lower terminal of coil 15 through "a" Iadi frequency 11 1 6 l 19- O II II infcoil' 5. Thisinduces corresponding cur- 20 serves to vary the inductive reactance of nts in coil 1 and the potential therebyprothe anode 3111311113 y compensatmg lIl P duced in this coil-is applied to the tube-2 durfor the reactance of coil 15. At the 8X-5 ing the intervals when the'chopper'contacts tremely high frequencles at which this syse pen; However, when the" chopper tern is designed to operate, the inherent ca+ contacts 25' close, a'path is provided in shunt pacity between the grid 13 and anode 14 of t oil 1, thr h co d n 26', i Thi t tube 11 provides a sufii-ciently low impedance path to feed back energy from the output to the input circuit of this tube and produces: regeneratlon, provlding the constants of the 1ength,thereb'y reducing the sensitivityof the circult are properly proportloned. :"feceive'r to the conti-nuous wave being Although detector tube 2 may be operated eivedj. Therefore-, "when the chopper om in any conventlonal fashion, it has beenf m t re clo d, ,.rgducedpot ti li applied found to work particularly well in this cir-T cuit with the grid return connected directly to the negative terminal of the filament and with the anode return connected directly to put circuit'of the tube 2, but tends to tune the alternating current of the chopper frequency "'more'or less neutralize the resistance of the 7 wave" produces a "relatively large current only serves to shunt some energy from the inwhole receiving circuit to a longer wave *to the -input circuit f-detector tube 2." Since the detector tube acts as a rectifying device,

flows in its output circuitflwhen'ever'continc.

passcondenser 22"p rovidesapathlfof low quen'cy'circuit (n ot1 shown); which'fnay be terminals of the detector tube. Chopper 25 c i ulate'duntilasettin-g 'isfobtained which'gives,

uous waves are being produced in coil 1. However, when no such waves are produced, thegrid of detector tube 4 is at the samepo tential as the cathode 3 and the operatlon of chopper has noefi'ect on the steady-state current flowingiintheprimary of audio frequency transformer 24.

Condenser 26 may frequency, there is an optimumnuniber of turns in, 0011 1 which gives best re'sults'i For this reason an'adjustable tap switch 28 is prol5 vided to adjust this coil to operateat 'di'flfer- I vulne tu y w s s fr v {-e nt frequencies, r. V I ;-.The source of continuous waves to be 8111-:

I 1 i-plified and detected neednotnecessarily be.-

1 an, antenna,:ofthezparticular formssh'own in I 4?? the-'drawing but' may =be of any suitable type;

j for {the reception 015 short ZWHIVGSXQ; Whateverbe replaced with a re .umsistance, undeuwhich conditionsit has been I l g I g ="detectorrespect vely, said-'couplln'g colls mu- It is found that when operating atafiy one tually reactingwith oneanother,"an'dchopper ative condition so as to more than neutralize the j-resist'ance thereof, a detector "having an .inputcircuit and an :outputcircuit, coupling ,coils in each of the circuits of said source,

said oscillator and the input circuit of said means shunting the input circuit' ofsaid detector gsaid chopper means being adapted to successively tune and detune the receiving syste'm afianaudible frequency.

here'unto set type ofyzantennavis provided, however it is 7 Q I preferablynlooselygcoupledmto coil 5.;

' .I:claim:".- V .,;1. In,a:;h1gh system, a source of continu-ouspwave; signals,

- frequency carrier :rie'ceiving .iQ.zkdetectingmeans,coupling meansbetween said I meansvincludingra threeielementvacuumgtube,

' detecting means and saidsource',regenerative,a

-- said source for increasing the;,transfer' ef- J 2-2 fic'lency ofz sa dglzcouphngamea'ns; andimeans tently at; a; toned'rejq'uency.-v

w mpr smg a chopper an'd-ian-impeda-nce'e1e- I MLHmQHtSEHI -SGPIQS adapted:lto-ishuntahigh frer .39 q y I rgy from; said .cletec'tor; :gintermit; 1

2. In agrveceivingesystem; 9r80111312 63,QfQCOIL EQatmuous wawes athr eselectrodegvacuum tube 1 {having its'inputcircuitcoupl-edto said source,

" i xmeans jfor fieedingback energyirom-ithe-outa 1 '1' putcircuit to thej'input'circuit-of said tube 1: 1whereby?"itr-functiolisqregeiieratively fa dea tecto fvhafing auinPut c rcuit and: an .out- .I.- a put"c1rcu1t,.the inputcircuit-ofsaidfqdetector J.

b ing upled; to said sour,ce,;. and-"Qchopper r 7 means; shunting the;inputwcircuitoi said detector or int rrupting ata; tone frequency "-.-,the"fapvphc ation ofcontlnuous waves--;tosaidq' detector ua tinuous-waves, azthree-electrode vaeuumgtube' havingitsiiiput circuitcoupledto said source, means including the gr1d:anol cap c y =11; saidi'rtube fer or-tuning the input and; output -v 5' circu t, of said tube asa unit to thezfmquency" of said ..wa,ves,--a port-ionaof said means conitrol l inggthe amount; of; energy fed backa-from.

I I theoutput circuit- 0f; said tube to the input 3-2 circuit through: said; grid anode :capacity, a

" 1 9 second; three electrodeyvacuum tube-l mi asa: port1on-,of'-;1ts:input circuit a ooil ind v ly coupled't the inputnc'ircuit,ozfisaidat} l first tube-,rza path shunting-said; coil, said h as" 

